Question

Define ecological pyramids and describe with examples, pyramids of number and biomass.

Answer 1

An ecological pyramid is a diagrammatic representation in the context of energy, biomass and number organisms showing the linkage between the various trophic levels of the ecosystem.

Pyramid of number- The pyramid that gives the number of organisms at each trophic level is called pyramid of number.

For example- oak → caterpillar → blue tit → sparrowhawk

The producer in the given food chain is the oak plant.

A caterpillar feeds on many oak leaves, the blue tit feeds on many caterpillars and finally, the sparrow hawk feeds on many the blue tits. Hence the number of organisms decreases at each trophic level.

Pyramid of biomass The pyramid that gives the total weight of the organisms at each trophic level is called pyramid of biomass.

For example- oak → caterpillar → blue tit → sparrowhawk

The total mass of organisms at each stage of a food chain decreases as the number of organisms decreases at each trophic level.